Brake controlling device



C. C. FARMER BRAKE CONTROLLI NG DEVI CE Filed Aug. 2, 19313 2 Sheets-Sheet l APPL! CATION ZONE RELEASE ZONE iii..

`INVENTOR .BY CLYDE C AHMEFQ A TTORN Oct. l5, 1935.

Figi 2 Sheets-Sheet 2 Oct. 15,1935. c. c. FARMER BRAKE CONTROLLING DEVICE Filed Aug. 2, 1955 Patented Oct. 15, 1935 UNHTED STTES ATENT OFFICE BRAKE CONTROLLING DEVICE Clyde C. Farmer, Pittsburgh, Pa., assigner to The Westinghouse Air Brake Company, Wilmerdinz, Pa., a corporation of Pennsylvania.

Application August 2, 1933, Serial No. 683,335

1 Claim.

McWhirter and Rankin J. Bush, Serial No. 644,-

448, led November 26, 1932.

With a self-lapping brake valve oi the above type, there is provided a movable abutment which is subject to the opposing pressures of a spring and the pressure of fluid supplied to the brake cylinder. When the spring is compressed by manual means against the abutment, the abutment is moved to open a valve for supplying fluid under pressure to the brake cylinder and when the brake cylinder pressure has been increased to a degree slightly exceeding the pressure of the spring, the abutment is moved by the brake cylinder pressure so as to lap or seat the supply valve.

The pressure of fluid supplied to the brake cylinder is thus limited or regulated according to the degree that the spring is compressed.

The spring is such that the maximum degree of pressure obtained in the brake cylinder by compression of the spring is considerably less than the full degree of pressure of the source of iiuid pressure such as seventy pounds with a main reservoir pressure of one hundred pounds.

It is, however, desirable to be able to secure the full main reservoir pressure in the brake cylinder under emergency conditions and the principal object of my invention is to provide means operative in the full service position of a self-lapping brake valve for supplying fluid at the full pressure of the source of fluid under pressure to the brake cylinder.

In the accompanying drawings; Fig. 1 is a diagrammatic view of a iiuid pressure brake equipment, showing my improvement embodiedl therein; Fig. 2 a section on the line 2 2 of Fig. 5, showing the construction of the electric switch portion of my invention, with the movable switch member in open circuit position; Fig. 3 a similar section, showing the movable switch member in its closed circuit position; Fig. 4 a section of the switch portion on the line 3 4 of Fig. 3; Fig. 5 a vertical section of the self-lapping brake valve device on the line 5 5 of Fig. 6 and Fig. 6 a section on the line 6 6 of Fig. 5.

As shown in Fig. 1, the equipment may comprise a self-lapping brake valve device I, a brake cylinder 2, a main reservoir 3, a double check valve device 4, and a double beat magnet controlled valve device 5.

The self-lapping brake valve device I shown in the drawings is similar to that disclosed the vpriorrapplication hereinbefore referred to, and

comprises a housing 6 in which is mounted a cylinder I containing a piston 8, subject on one side to the pressure of a spring 9 and rhaving the chamber i!! at the opposite side open t-o the brake l cylinder 2, by way oi pipe II.

The piston 8 is adapted to control the operation of a release valve I2 and a fluid pressure supply valve I3. A movable member I4 bears against the upper end of spring 9 and a lever I5, pivotally 10 mounted on the cylinder 1 is pivotally connected to the member I 4.

A shaft I6 is mounted in suitable bearings within the housing 6 and secured to said shaft is an arm I1 having a roller I8 at its i'reeend which is il adapted to engage the face of a downwardly ex tending arm I9 of the lever I5, when the shaft I6 is rotated in a counter-clockwise direction.

Secured to a section of the shaft I6 which eX- tends outside of the housing 6 is a treadle 20. 20 Another cylinder 2I is mounted in the housing 8 and contains a piston 22, the chamber 23 at the upper face oi which is connected, through pipe 2B with the main reservoir 3. A link 25 is pivotally connected to the piston 22 and to a mem- 25 ber 26 which is pivotally carried on a supporting bracketZ'l.

A lever 28 is secured to the shaft I6 and a link 29, pivotally connected to said lever, is pivotally connected to the member 26. $0

Fluid under pressure acting on the piston 22 in chamber 23 urges the piston 22 downwardlyand tends, through the linkage connections to rotate the arm 28 and shaft I6 in a counter-clockwise direction. As alconsequence, the pedal lever 20 S5 must be held depressed by the foot of the operator, in order to maintain the parts in release position, as shown in Fig. 1.

When it is desired to apply the brakes, the pressure of the foot on the treadle 20 is relieved 4.0 to a certain extent, to permit the movement of the pedal lever 20 into the application zone, by the action of fluid pressure on the piston^22. In this movement, the roller I8 is moved into engagement with the working face of the arm I9 and 45 then the lever I5 is rotated so that the member I4 operates to compress the spring 9.

The pressure of spring 9 then operates to move piston 3 downwardly, so as to rst seat the release valve I2 and then unseat the supply valve 50 i 3, so that fluid under pressure is supplied by way of pipe 30 to chamber .I0 and to the brake cylinder 2.

When the pressure of uid acting in chamber i9, slightly exceeds' the opposing pressure o1' 55 spring 9, the piston 8 is moved upwardly until the supply valve I3 is seated, thus cutting oil the further flow of fluid to the brake cylinder.

'I'he brake cylinder pressure may be increased by permitting a further upward movement of the pedal 2Q, so as to cause a further compression of the spring 3. The piston 8 is then caused to again move downwardly so as to unseat the supply valve I3 and permit the further supply of fluid under pressure to the brake cylinder until the brake cylinder pressure acting in chamber III again slightly exceeds the pressure of the spring 9, the piston 8 then being again moved upwardly to permit the valve I3 to seat.

In the above described operation of the brake valve device, the pressure of fluid supplied to the brake cylinder is determined by the degree to which the spring 9 is compresse-d. According to the principal object of my invention, means are provided by which the brake cylinder pressure may be built up to the full pressure carried in lthe main reservoir, by permitting the pedal lever 20 to move to or nearly to the limit of its upward movement through the application Zone.

For this purpose, the double beat magnet controlled valve device 5 is provided, which comprises a magnet 3l and double beat valves 32 and 33 adapted to be controlled by said magnet.

The valve 32 controls communication from the main reservoir supply pipe 38 to a pipe 34 which -leads to one side of the double check valve device 4, and the valve 33 controls communication from pipe 34 to an atmospheric exhaust port 33.

For controlling the circuit of the magnet 3l, a switch device is provided, comprising a casing 36 secured to the housing 6 on the side where the pedal 20 is located. Within the casing is mounted a plate 31 of insulating material, to which is secured a block 38 of insulating material.

Mounted on the block 33 are fixed contact members 39 and 40, the contact member 39 being connected to a wire 4I leading to a source of electric current, such as the trolley, and the other contact member 43 being connected to a wire 42 leading to one terminal oi the magnet 3I, the other terminal of which is connected to ground.

Mounted in the casing 331 on a pivot pin 43 is an arm 44 to which is secured a switch carrying member 45 of insulating material. The member 45 carries a bridging contact member 43, which is adapted to bridge the contacts 39 and 49. Adjacent to the pivot pin 43, an adjustable screw 41 is threaded into the arm 44, the end of the screw being engageable by a member 48 carried by the pedal lever 2).

The screw 41 is adjusted as desired, so that the member 48 will engage the end of the screw 41 when the pedal lever 2B has been permitted to move up nearly to the upper limit of the application Zone.

The double check valve device 4 contains a double check valve 49 which is operated by fluid under pressure supplied by operation of the brake valve device to open communication from the brake cylinder supply pipe II to the brake cylinder 2 and to close communication from the by-pass supply pipe 34 to the brake cylinder. When fluid under pressure is supplied by operation of the magnet valve device 5 to pipe 34, the double check valve 49 is operated to open communication from the pipe 34 to the brake 4cylinder and to close communication from the pipe I I to the brake cylinder.

In operation, with fluid under pressure supplied from the main reservoir to the chamber 23 above the piston 22, the piston 22 is urged downwardly, tending to rotate the shaft I6 in a counter-clockwise direction, so as to cause the arm I1 to move and the roller I8 to engage the arm 21 and the operator must maintain foot 5 pressure on the pedal 28, in order to prevent this movement.

If it is desired to apply the brakes, the operator permits the pedal 28 to rise intothe application zone, so that the spring 9 is compressed to the 10 extent that the pedal is allowed to move upwardly in the application zone.

The pressure thus exerted by the spring 9 on piston 8 causes the piston to move downwardly, so as to first effect the seating of the release 15 valve I2 and then the unseating of the supply valve I3. Fluid under pressure is then supplied from the main reservoir pipe 38 to the brake cylinder pipe I i and thence past the double check Valve 49 to the brake cylinder 2.

When the pressure of fluid supplied to chamber Ill and the brake cylinder slightly exceeds the opposing pressure of the spring 9, the piston 8 is moved upwardly suiiiciently to close or seat the Supply valve I3 and thus cut off the further 42:5 supply of fluid to the brake cylinder.

The pressure of fluid supplied to the brake cylinder may be further increased by permitting a further upward movement of the pedal 20, so as to cause a further compression of the spring 30 9, as will be evident.

If the operator desires to obtain the full main reservoir pressure in the brake cylinder or if the operator should accidentally or intentionally remove his foot the movement of the pedal lever g5 to or nearly to the upper limit of the application zone will cause the member 48 to engage the screw 41 and then shift the arm 44 upwardly, so that the contact 46 bridges the contacts 39 and 4U, 40

A circuit is thus closed through the magnet 3|, so that the magnet is energized and thereby the valve 33 is moved to its seat, cutting off cornmunication from pipe 34 to the exhaust port 35, and the valve 32 is unseated, so that fluid under 45 pressure is supplied from the main reservoir pipe 38 to pipe .34.

If fluid under pressure has previously been supplied to the brake cylinder through pipe II, the double .check valve will be seated at its lower 50 seat, but as soon as the pressure of fluid supplied through pipe 34 exceeds the fluid pressure acting above the double check valve, the double check valve will be shifted to its upper seat, and communication will be opened from pipe 34 to 55 the brake cylinder, so that the brake cylinder pressure will then be built up to the full main reservoir pressure.

The brakes may be released by moving the pedal 28 to its full release position, as shown in `50 Fig. 1, and the circuit of the magnet 3l being opened when the member 48 moves away from the screw 41, by the action of spring 50 on the arm 44, the valve 32 is moved to its seat by the spring 5I and the valve 33 is unseated, permit- 55 ting fluid in the brake cylinder to exhaust through pipe 34 to the atmosphere by way of the exhaust port 35.

It will now be evident that with my improved equipment, the operator may at any time, quickly obtain full main reservoir pressure on the brake cylinder, as in case of an emergency, or full main reservoir pressure will be obtained in the brake cylinder, if the operator should accidentally or intentionally remove his foot from the foot pedal. g5

the brake cylinder, a spring, a movable abutment subject to the opposing pressures of said spring and the pressure of uid supplied to the brake cylinder for operating said valve, and a manually operable member movable in an application zone 5 in which zone the pressure of said spring on said abutment is varied, of means operable upon move-V ment of said member to a certain position within the limits of said application Zone, for supplying fluid under pressure from said source of uid 10 under pressure to the brake cylinder.

CLYDE C. FARMER. 

